This invention relates to apparatus for electrically interconnecting flexible circuit strips and etched circuit boards, one with the other. In particular, the present invention relates to high density connectors with decreased insertion losses and cross-talk between the conductive paths.
Over the last decade, great strides have been made in miniaturization of electronic circuit components. However, the reduction in the size of the connectors needed to interconnect those devices into subsystems has not progressed nearly as quickly. A decade ago the connectors with the highest density required 0.025 of a square inch of board space for each conductor in the connector. Today, the highest density connectors require 0.011 of a square inch of board space for each conductor.
Shin-Etsu Polymer Co., Ltd., of Tokyo, Japan, manufactures and markets an anisotropically pressure-sensitive electroconductive composite material, sold as AF and MAF interconnector material, in sheet form. That material has electrically conductive fibers uniformly dispersed in the matrix of an electrically insulating polymer with each conductive fiber aligned substantially perpendicularly to the plane of each surface of the sheet. When this material is compressed, surface to surface, a very low electrical resistance is observed in the direction perpendicular to the plane of the surfaces of the sheet (through the sheet), and a high insulative resistance is observed in all other directions within the plane of the surface of the sheet. Several patents have issued on this material and its applications which include U.S. Pat. Nos. 4,199,637; 4,210,895; 4,252,391; and 4,252,990.
A connector configuration in which the density of the conductive paths can be increased significantly over those currently available with no increase in path resistance, capacitance or cross-talk is highly desirable. The present invention provides a connector wherein the conductive paths can be packed one every 0.004 (flexible circuit to flexible circuit) to 0.008 (etched circuit board to etched circuit board or etched circuit board to flexible circuit) square inches of board space with the same or greatly improved resistive, capacitive and cross-talk characteristics over prior art connectors.